Thermal imaging systems are usually based on IR-camera systems analyzing the infrared part of the electromagnetic spectrum to carry out temperature measurements. These systems are very accurate but also very expensive. A “low-cost” thermal-vision-system based on a standard CCD color video camera in combination with an image processing system is presented. The system was developed to visualize the temperature distribution inside a plasma-reactor. The temperature of the heat-treated work pieces lies in the range of 450°C to 650°C. By analyzing the thermal light emission of these objects a temperature map can be made to visualize and measure temperature differences of the reactor interior.